Heat oven to 350ºF. To toast walnuts, place walnuts evenly on baking sheet and bake 10 minutes or until fragrant. Set aside until ready to use.
Line an 8x8-inch square pan with parchment paper, leaving a 2-inch overhang; set aside until ready to use.
Meanwhile, in a large saucepan, combine sugar, butter, and evaporated milk. Bring to boil (cover with a lid for about 1 minute to make sure sugar is dissolved). Remove lid and decrease to medium heat. Insert candy thermometer into liquid and continue boiling for 5 minutes, stirring frequently until thermometer reaches 234°F (this is important, don't walk away!).
Remove saucepan from heat and add chocolate chips. Stir until completely melted. Stir in marshmallow creme and vanilla extract until there are no white streaks. Fold in cranberries and toasted walnuts until evenly distributed.
Pour fudge mixture into prepared pan and let set completely. Use the parchment paper to lift the fudge out of the pan and cut into squares before serving.
Notes
You don't need a fancy candy thermometer. I grabbed mine at the grocery store and it worked just fine!
I originally made this recipe with dried cherries (1:1 ratio to cranberries) and it was fantastic! Feel free to test out other dried fruits as well. Candied orange peels would be SO good!